Device for connecting metallic sleeves to finned reinforcing bars

ABSTRACT

Apparatus is disclosed for connecting sleeves to fin-equipped reinforcing bars for concrete, which bars consist of a material which is harder than the material of said sleeve. The sleeve is deformed by pressure in such a way that the fins of said reinforcing bar means press themselves into the sleeve and positively interlock therewith while the deformation of the sleeve is effected in sections over the length of the sleeve.

United States Patent 11 1 Leonhardt et al.

[111 3,835,690 [451 Sept. 17, 1974 Filed:

DEVICE FOR CONNECTING METALLIC SLEEVES TO FINNED REINFORCING BARSInventors: Fritz Leonhardt, Stuttgart; Volker Hahn, Leinfelden; WernerFastenau, Esslingen-Rudern, all of Germany Ed. ZublinAktiengesellschaft, Stuttgart, Germany Oct. 26, 1971 Appl. No.: 192,435

Related U.S. Application Data Division of Ser, No; 872,950, Oct. 31,1969,

abandoned.

Assignee:

Foreign Application Priority Data Nov. 2, 1968 Germany 1806665References Cited UNITED STATES PATENTS Scott 72/412 1,727,896 9/1929Mraz 72/412 1,813,520 7/1931 White 72/415 2,202,125 5/1940 Temple 72/4152,831,377 4/1958 Harvey 72/453 2,940,497 6/1960 Herrstrum 1 72/4532,941,430 6/1960 Klingler 72/453 3,263,465 8/1966 Way 72/412 3,326,0296/1967 Portcr 72/45'1 Primary ExaminerCharles W. Lanham AssistantExaminer-Gene P. Crosby Attorney, Agent, or Firm-Walter Becker [57]ABSTRACT Apparatus is disclosed for connecting sleeves to finequippedreinforcing bars for concrete, which bars consist of a material which isharder than the material of said sleeve. The sleeve is deformed bypressure in such a way that the tins of said reinforcing bar means pressthemselves into the sleeve and positively interlock therewith while thedeformation of the sleeve is effected in sections over the length of thesleeve.

8 Claims, 15 Drawing Figures /mnm.s.-

PAIENIEBSEP 1 mm sum 1 u; 3

DEVICE FOR CONNECTING METALLIC SLEEVES TO FINNED REINFORCING BARS Thisis a divisional application of co-pending Ser. No. 872,950, Leonhardt etal., filed Oct. 31, 1969, now abandoned.

The present invention relates to a method of and device for connectingmetallic sleeves to finned reinforcing bars. Such a method is employed,for instance, in

' order to interconnect reinforcing bars.

It is an object of the present invention to provide a method and device,as set forth above, which will make it possible to connect the sleevessafely and in a very simple manner to finned reinforcing bars withoutthe exercise of relatively high forces.

These and other objects and advantages of the invention will appear moreclearly from the following specification in connection with theaccompanying drawings, in which:

FIG. 1 illustrates an axial section through a device according to thepresent invention. I

FIG. 2 represents a section taken along the line II-II of FIG. 1.

FIG. 3 illustrates the device according to FIG. 2, but with the pressdie in opened condition, i.e., prior to the pressing operation.

FIG. 4 illustrates a cross section through a sleeve connection accordingto the invention with the stress diagram pertaining thereto.

FIG. 5 is a cutout of a modification of a sleeve connection.

FIG. 6 is a portion of the sleeve connection as seen in longitudinaldirection.

FIG. 7 illustrates the arrangement of the device according to FIGS. 1 3for producing the sleeve connection of FIG. 6.

FIG. 8 represents an arrangement of the device subsequent to thearrangement of FIG. 7.

FIG. 9 is a cross section through a sleeve according to the invention.

FIG. 10 shows the sleeve of FIG. 9, but in reverse arrangement.

FIGS. 11 and 12 respectively illustrate two modified sleeves somewhatsimilar to those of FIGS. 9 and 10.

FIG. 13 illustrates a sleeve composed of one cylindrical member only.

FIGS. 14 and 15 respectively illustrate two further embodiments ofsleeves for interconnecting steel inserts.

With the method according to the present invention for connectingmetallic sleeves to finned reinforcing bars, the sleeve which consistsof a softer material than the reinforcing bar is deformed by pressingwhile the fins or ribs of the reinforcing bar are pressed for positiveengagement into the inner sides of the sleeve, the deformation of thesleeve being effected stepwise over sections of the length of thesleeve. By subdividing the deformation in timewise successive deformingphases, a relatively small force for deforming the sleeve will sufficeso that it is possible to connect the sleeve also, for instance, on abuilding lot to the reinforcing bar or bars while using light devices.Expediently, the deformation on adjacent sections are effectedsuccessively while the deformation can be carried out in a simple mannerfrom one end of the sleeve toward the other end. Furthermore, it isadvantageous to carry out the deformation over sections of equal lengthso that a simple method or process is obtained.

For purposes of increasing the strength of the connection of the sleevewith the respective reinforcing bar, the deformationis effectedsubstantially uniformly over the entire circumference of the sleeve. Inthis connection the deformation of the sleeve may be effected in atleast two different radial directions, preferably offset to each otherby In order to avoid a decrease of the fatigue strength of the sleeveconnection in view of a too strong transverse pressure, it is expedientto press the sleeve along its intermediate range of its length at agreater force against the reinforcing rod than at least against one end.The pressing force decreases from the intermediate range of the sleeveexpediently to the end thereof in a steady way while the end of thesleeve advantageously surrounds the reinforcing bar in a pressure-freemanner. This may be realized in a simple manner by arranging the sleevein the area of its end, prior to the deformation of the sleeve bypreferably conically widening the sleeve opening, with a greater radialplay than in the intermediate range of the sleeve. In this way alsosharp inner edges of the sleeve within the area of its ends will beprevented from engaging the reinforcing bar or bars.

According to a further feature of the invention, with the deformation ofa partial section of the length of the sleeve, the pressing force at theend of a partial section decreases preferably in a steady way so that atthe merging area from the pressed to the unpressed portion of the sleeveno sharp edges but only a rounded portion will be formed.

A butt connection between finned reinforcing rods, which connection iseffected in particular in conformity with the above mentioned method, ischaracterized primarily by a pressing sleeve which positively sur roundsboth reinforcing bars and the material of which is softer than thematerial of the reinforcing rods so that in a simple manner a firmconnection will be realized between the reinforcing bars.

For purposes of increasing the fatigue stress resistance of the sleeveconnection, the sleeve opening is expediently at least toward one end ofthe sleeve preferably to both ends of the sleeve, conically widened.

A device for carrying out the method according to the present inventionwith two press dies adapted to be moved relative to each other andsupported by a corresponding supporting means is characterized primarilyby designing the press surfaces of the press dies shorter in axialdirection than the sleeve, said press dies being widened at their ends.In view of this design, the device or the press may be relatively smalland light so that they can easily be handled in a simple manner also onareas which are somewhat difficult to get at. The broadening at the endsof the die opening will assure that the sleeve at the end of eachsection or portion which has been pressed will not be damaged but will,through the intervention of a rounded portion, merge with the notpressed portion. Advantageously, the

broadening portions are formed by roundings.

An advantageous further development of the device according to theinvention is characterized by a step control device which is connectedto the holding means for stepwise feeding the device so that the feed ofthe press can be determined precisely and that in a simple manner acomplete pressing of the sleeve over the entire length thereof will beassured. Expediently, the step control device has a gauge detachablyconnected to the reinforcing bar. This gauge is provided with recesseslocated one behind the other in the longitudinal direction of thereinforcing bar for a pawlmovably mounted on the supporting means. Inthis way the step control device can be aligned in a simple mannerrelative to the reinforcing bar. In order to be able to detach the gaugetransverse to the reinforcing bar, the gauge is of a U- shaped crosssection while expediently comprising a clamping screw or clamping wedgefor connection to the reinforcing bar. The pawl may, in a simple manner,be joumalled on the holding means for pivoting about a pivotperpendicular to the central axis of the die opening.

Referring now to the drawings in detail, and FIGS. 1 3 thereof inparticular, the arrangement shown therein comprises a tubular cylinder 1which is closed at one end thereof by a, for instance, detachable cover2 or by a one-piece end wall, while the other end is open. In thecylinder 1 there is reciprocably mounted a piston 3 which is providedwith a corresponding seal 4. Piston 3 has that end face 5 thereof whichfaces away from the cover 2 provided with nonillustrated connectingmeans for detachable and exchangeable connection of a part 6 of a pressdie 6, 7. The other part 7 of this die may to that end of the pipe whichfaces away from the cover 2 and forms the cylinder 1, be easilyexchangeably connected by means of a bayonet joint 8. This end of thepipe which forms the cylinder 1 is provided with an axial slot 9, thewidth of which is greater than the diameter of the sleeve to be deformedwhile the height of the slot 9 equals at least the diameter of thesleeve 10 plus the height of the part 7 of the press die. At its rearside the piston 3 is provided with a recess 11, the bottom of which, hasan eye 12. This eye 12 is located opposite an eye 13 on the inner sideof the cover 2 while between the two eyes 12, 13 there is clamped apreloaded tension spring 14. In the cover 2 of the cylinder 1 there isfurthermore provided a passage 16 which leads into the pressure chamberand is equipped with nonillustrated connecting means for connection to apressure line.

With the embodiment illustrated in FIGS. 1 3 it is intended to connectthe sleeve 10 which in its starting position is cylindrical to the twooppositely located ends of two finned reinforcing rods or bars 17, 18 insuch a way that the two reinforcing rods or bars 17, 18 are firmlyinterconnected by the sleeve 10. The sleeve 10 which in its startingcondition has an inner diameter which is greater than the outer diameterof the reinforcing bars 17, 18, is to this end first placed upon the twoends of the reinforcing bar 17, 18 in such a way that the two end facesthereof will be located directly adjacent to each other. Thereupon, thepressing device is, prior to the connection of the part 7 of the pressdie, slipped upon the sleeve in such a way that the sleeve 10 or thereinforcing bars 17, 18 are located in the slot 9 of the pipe formingthe cylinder 1 and that the press surface 19 of the pressing die portion6 engages the circumference of the sleeve 10. Thereupon the press diepart 7 may, by means of a bayonet joint 8, be connected to that end ofthe cylinder 1 forming a pipe which protrudes beyond the circumferenceof the sleeve 10. This connection will be so effected that the sleeve 10is located between the die surfaces 19, 20 of the press die 6, 7, whichsurfaces form the die opening.

The length of the press surfaces 19, 20 of the press die 6, 7 is, whenmeasuring in the longitudinal direction of the sleeve 10 or in axialdirection of the opening of the die, shorter than the length of thesleeve 10. As a result thereof, the sleeve 10 has to be deformedstepwise over sections of its length while for purposes of deformationof each portion or section only a relatively low pressing force isrequired so that a weight saving light and space saving construction ofthe pressing device will be obtained.

For purposes of deforming a portion or section of the sleeve 10, apressure medium such as oil under pressure is conveyed through thepassage 16 into the pressure chamber 15 of the cylinder 1 so that thepiston will be advanced against the thrust of spring 14, and the sectionor portion of the sleeve 10 will be pressed against the circumferentialsurface of the respective reinforcing bar 17, 18. The ribs or fins 21 ofthe reinforcing bar are pressed into the inner surface 22 of the sleeve10 which is of a softer material than the reinforcing bars 17, 18 sothat the sleeve 10 will be positively connected to the reinforcing bars17, 18. Following the deformation of the first section according to FIG.1, the adja cent section is deformed whereupon that section will bedeformed which is adjacent to the last mentioned section, etc. Thecorresponding successive positions of the press die 6, 7 are illustratedin FIG. 1 by 23a, 23b and 23c in dot-dash lines. The deformation of thesleeve 10 is thus effected in a continuous manner stepwise from one endof the sleeve toward the other end over equal lengths.

In order to be able to precisely fix the length of the individualsections, the device according to the present invention is provided witha step control mechanism. This step control mechanism 24 is equippedwith a gauge 25 which is of a U-shaped cross section and the inner widthof which is greater than the diameter of the reinforcing bars l7, 18 sothat the gauge 25 is adapted in a transverse direction to thelongitudinal direction of the reinforcing bars 17, 18 to be placed uponone of the said reinforcing bars adjacent the sleeve 10. In a leg of thegauge 25 there is mounted, for instance, a clamping screw 26 withthread, which clamping screw forms a wing screw by means of which thegauge 25 can be firmly clamped against the respective reinforcing bar17. At the circumference of the pipe which forms the cylinder 1 there ismounted on arm 27 which is pivotable about an axis 28 which isperpendicular to the piston axis and to the longitudinal axis of thereinforcing bars 17, 18. The said arm 27 is at one end thereof equippedwith a pawl 29 which is directed toward the central axis of thereinforcing bars 17, 18. The pawl 29 has at the circumference of thegauge 25 associated therewith locking recesses 30 which, in thelongitudinal direction of the gauge 25, are located one behind the otherand which may be engaged by the locking bar 29. By moving the devicealong the sleeve 10 and by introducing the pawl 29 into the respectivesuccessive recesses 30, the length of the sections of the sleeve 10which are to be successively deformed may be precisely ascertained.

As shown in FIG. 1, the press surfaces 19, 20 of the die parts 6, 7 areat their ends respectively provided with rounded areas 31 in such a waythat the die opening is rounded at its ends and widened in diameter.This brings about that after the deformation of one portion or sectionof the sleeve 10 there is formed a rounded transfer merging area 32merging with the not-yet deformed portion of the sleeve so that damageto the sleeve 10 will be avoided at any rate.

By deforming the sleeve 10 in sections, it is also possible withoutdifficulties to vary the pressing forces from section to section atwhich the sleeve 10 is pressed against the reinforcing bars 17, 18.Expediently, according to FIG. 4, the sleeve 10 is within the range 33of the center of the length of the sleeve pressed against thereinforcing bars 17, 18 to a greater extent than in the areas 34 of itstwo ends. The corresponding pressing forces are illustrated in FIG. 4 byarrows of greater length. The length of the intermediate range 33 is sose lected that it will be effective at both ends of the reinforcing bars17, 18 over as great a length as possible. The pressing force in theranges 34 may also decrease steadily toward the ends of the sleeve 10while the merging of the pressing force between the ranges 34 and 33 maylikewise be steady or continuous.

Expediently, the inner surface of the sleeve 10 will at the ends thereofsurround the reinforcing bars 17, 18 in a pressure-free manner. This maybe realized for instance by providing the opening of sleeve 10 at theends thereof with rounded widening portions 35 according to FIG. 5 sothat the sleeve 10 will at its ends not at all engage the reinforcingbars 17, 18.

When deforming a section or portion of the sleeve 10 by means of atwo-sectional press die 6, 7 there will in the dividing plane of thispress die 6, 7 at the sleeve 10 sometimes be encountered a bead 36 ofthe material at two oppositely located sides of the sleeve 10 while theinner surface of sleeve 10 will likewise also in this range not engagethe circumference of the reinforcing bars 17, 18, but hollow spaces 37will form. In order to avoid this form of the sleeve 10 in conformitywith FIG. 6, the deformation of the sleeve is effected preferably inoffset direction by 90 in conformity with FIGS. 7 and 8. The sleeve formaccording to FIG. 6 will be obtained after the deformation with thepressing device occupying the position shown in FIG. 7. After the dies6, 7 have been opened, the pressing device is pivoted by 90 to aposition shown in FIG. 8 so that now the sleeve 10 also within the areaof the now formed beads 36 can be pressed firmly against thecircumference of the reinforcing bars 17, 18. In this connection it ispossible to deform all of the sections of the length of sleeve 10 firstat an angular position of the pressing device and subsequently in areverse direction or in the same direction while changing the angularposition of the pressing device to carry out once more the deformationin sections. However, it is also possible to employ the pressing deviceat each section directly one after the other in two different angularpositions and only then to deform the next section of the sleeve 10.

FIG. 9 shows a sleeve according to the invention with a sleeve-likecollar 101 which at one of its ends forms a trumpet-shaped widenedanchor portion 102 which thus is widened from the collar 101. The sleeveis with its collar 101 slipped onto the end 103 of a steel insert 104and is in radial direction (arrow 105) compressed inwardly against thesteel insert 104 so that the sleeve will be firmly held. According tothe specific illustrated embodiment, the steel insert 104 is formed by aconcrete finned steel the circumference of which has fins or ribs 106.When compressing the collar 101 the ribs 106 are pressed into the innersurface of the sleeve 101 so that the latter following its compressionwill positively be arrested relative to the steel insert 104. The anchorpart 102 merges by a ring portion 107 having a relatively slightcurvature with the sleeve 101 while the free end of the ring member 107has a bead 108 located in a radial plane.

According to the embodiment of FIG. 9, the anchor part 102 diverges inthe direction of the end 103 of the steel insert 104 so that the steelinsert 104 is anchored against pull in the direction of the arrow 109.

According to the embodiment illustrated in FIG. 10, the anchor part 102which incidentally is of the same construction has its widened portiondirected to the center of the steel insert 104 while the steel insert104 also in this instance is arrested against pull in the direction ofthe arrow 109. The anchoring force of the anchor part 102 is, however,with the embodiment of FIG. 10, greater than with the embodiment of FIG.9.

FIG. 1 1 illustrates that the anchor part 102a may also have its outerrange curved to such an extent that the annular bead 108a is toward therear at least partially directed in the direction of the sleeve 101.

According to the embodiment of FIG. 12, the sleeve 101b is designed soas to form a part which is separate from the anchor part 102b while theanchor part 102k expediently has its smaller end face 111 restingagainst an end face 110 of the sleeve 10lb.

If the adhesive or bond stresses are not too high, the sleeve may alsobe formed by a continuous cylindrical sleeve l01c which is likewiseconnected to the steel insert 104 in the form of a compressed sleeve.The circumferential surface 102a of the sleeve 1010 will in thisinstance by adhesive friction assure a sufficient anchoring which mayfurthermore be increased by an end face 102d of the sleeve 1010 whichend face acts as abutment or anchoring surface.

According to the embodiment of FIG. 14 two slack steel inserts 104 havetheir directly adjacent ends 103 connected to each other by a commonsleeve 112. Sleeve 1 12 is formed by means of two sleeves in conformitywith FIGS. 9 and 10, the widened portions of which are directed towardseach other while the collar 101 of each sleeve is connected to the end103 of a steel insert 104. The anchor portions 102 which pertain to thetwo sleeves and are facing toward each other are placed against eachother with their annular beads 108 and are connected to each other by awelding seam 113. In this way the steel inserts 104 are on one handfirmly connected to each other and on the other hand are anchored in theconcrete.

FIG. 15 illustrates an embodiment which is similar to that of FIG. 13.Around the two ends 103 of two successive steel inserts 104 there isprovided a common sleeve 101e which is substantially cylindrical andwhich in the form of a collar is in the manner described above connectedto the steel inserts 104. This circumferential surface 102a as well asthe end faces l02f of the sleeve 101e act as with the embodiment of FIG.13 as anchoring means.

By means of the sleeve according to the invention, slack steel insertscan in a simple manner be ascertained and connected. In particular, thesleeve will, while requiring a minimum of space, assure a safe anchoringof slack steel inserts. Furthermore, the sleeve according to theinvention is also suitable for interconnecting successive steel insertsarranged adjacent to each other, while the sleeve itself is simple inconstruction and inexpensive to produce.

It is, of course, to be understood that the present invention is, by nomeans, limited to the particular showing in the drawings, but alsocomprises any modifications within the scope of the appended claims.

What we claim is:

1. An apparatus for joining sleeve means surrounding concretereinforcing bar means to the latter, which includes: cylinder meanshaving transverse passage means therethrough for receiving concretereinforcing bar means and at least a portion of sleeve means surroundingthe same, fluid operable piston means reciprocable in said cylindermeans, first die means detachably connected to said piston means forexerting deforming pressure upon sleeve means to be connected to barmeans introduced into said passage means, second die means detachablyconnected to said cylinder means and forming the counterpart to saidfirst die means for deforming said sleeve means from the opposite sidewith regard to the portion to be deformed by said first die means, thefront and rear edge portions of said first and second die means whenlooking in the longitudinal direction of said sleeve means flaring awayfrom each other, and a stepping mechanism for stepwise advancing saidbar means with said sleeve means.

2. An apparatus in combination according to claim 1, in which theflaring edge portions of die means are rounded.

3. An apparatus according to claim 1, in which said stepping mechanismcomprises gauge means detachably connected to said bar means, said gaugemeans having recess means arranged one behind the other when looking inthe direction of said bar means, and pawl means connected to saidcylinder means for successively engaging said recess means.

4. An apparatus according to claim 3, in which said gauge means is ofU-shaped cross section and comprises a clamping screw for detachableconnection to said bar means.

5. An apparatus according to claim 3, in which said pawl means ispivotable about an axis extending in a direction transverse to thelongitudinal axis of said pas sage means.

6. An apparatus according to claim 3, which includes spring meansarranged within said cylinder means and continuously urging said pistonmeans in the direction toward said passage means.

7. An apparatus in combination according to claim 1, in which saidsecond die means is connected to said cylinder means by a bayonet joint.

8. An apparatus in combination according to claim 1, in which thatportion of said cylinder means which has said second die means arrangedtherein is provided with axial slot means having a width in excess ofthe diameter of said sleeve means.

1. An apparatus for joining sleeve means surrounding concretereinforcing bar means to the latter, which includes: cylinder meanshaving transverse passage means therethrough for receiving concretereinforcing bar means and at least a portion of sleeve means surroundingthe same, fluid operable piston means reciprocable in said cylindermeans, first die means detachably connected to said piston means forexerting deforming pressure upon sleeve means to be connected to barmeans introduced into said passage means, second die means detachablyconnected to said cylinder means and forming the counterpart to saidfirst die means for deforming said sleeve means from the opposite sidewith regard to the portion to be deformed by said first die means, thefront and rear edge portions of said first and second die means whenlooking in the longitudinal direction of said sleeve means flaring awayfrom each other, and a stepping mechanism for stepwise advancing saidbar means with said sleeve means.
 2. An apparatus in combinationaccording to claim 1, in which the flaring edge portions of die meansare rounded.
 3. An apparatus according to claim 1, in which saidstepping mechanism comprises gauge means detachably connected to saidbar means, said gauge means having recess means arranged one behind theother when looking in the direction of said bar means, and pawl meansconnected to said cylinder means for successively engaging said recessmeans.
 4. An apparatus according to claim 3, in which said gauge meansis of U-shaped cross section and comprises a clamping screw fordetachable connection to said bar means.
 5. An apparatus according toclaim 3, in which said pawl means is pivotable about an axis extendingin a direction transverse to the longitudinal axis of said passagemeans.
 6. An apparatus according to claim 3, which includes spring meansarranged within said cylinder means and continuously urging said pistonmeans in the direction toward said passage means.
 7. An apparatus incombination according to claim 1, in which said second die means isconnected to said cylinder means by a bayonet joint.
 8. An apparatus incombination according to claim 1, in which that portion of said cylindermeans which has said second die means arranged therein is provided withaxial slot means having a width in excess of the diameter of said sleevemeans.